[rcomeau]

All the electronics are powered s’y by the 12v battery and the 12v battery is managed by modules and software that charge it from the traction battery (Ayepace can correct me if I got that wrong) regardless if it is driving, being charged or just sitting there.
Maybe the electronics are too twitchy to have the power source swapped on the fly (unlike a laptop that manages it just fine) or some other issue that makes it too fragile, using the 12v as a permanent buffer seems have been the consensus as it seems to be common to EVs in general. As someone whose car has been in the shop 3 times in the last year alone for 12v issues, I question their rationale.

 

[Ayepace]

The smaller 12V auxiliary battery was done away with starting in 21MY so that eliminates half the problem. Does it introduce a single point of failure? Well, it only provided 12V for 3 things and the larger 12V battery could work just as well for them. I don't know the reasoning behind putting the small battery in the I-PACE. It had been eliminated from other JLR products, where it had been used to support 12V during the stop part of the ICE stop/start feature, several years before the I-PACE introduction.

Software updates were needed to ensure the charging process worked correctly. Apparently they found situations where it didn't work. It was probably re-worked in eliminating the auxiliary battery, too.

However, we're still at the mercy of the battery not going bad and the relays/contactors involved don't go bad when the requests are made to charge or stop charging.

rcomeau, you got it right per the workshop manual info. The original programming may have been on a different page though.

 

[wuxyjj@yahoo.com]

The smaller 12V auxiliary battery was done away with starting in 21MY so that eliminates half the problem. Does it introduce a single point of failure? Well, it only provided 12V for 3 things and the larger 12V battery could work just as well for them. I don't know the reasoning behind putting the small battery in the I-PACE. It had been eliminated from other JLR products, where it had been used to support 12V during the stop part of the ICE stop/start feature, several years before the I-PACE introduction.

Software updates were needed to ensure the charging process worked correctly. Apparently they found situations where it didn't work. It was probably re-worked in eliminating the auxiliary battery, too.

However, we're still at the mercy of the battery not going bad and the relays/contactors involved don't go bad when the requests are made to charge or stop charging.

rcomeau, you got it right per the workshop manual info. The original programming may have been on a different page though.

Ayepace, I think in one of your post it mentioned that one of the reason to have the smaller 12v is that when other went bad, the car will still have the power to break and stop safely.

 

[Ayepace]

You can still brake and stop safely. It just won't have all the brake assist that is has with the 12V (like non-power brakes in the good old simple days).

 

[wuxyjj@yahoo.com]

You can still brake and stop safely. It just won't have all the brake assist that is has with the 12V (like non-power brakes in the good old simple days).

My wife almost had an accident when her car lost power break and power steering when driving a few years ago. She had a hard time to control the car when that happened.

 

[Ayepace]

I learned to drive in a car without: power brakes, power steering, power seats, power windows, power heated mirrors, heated windscreens (front and rear), air conditioning, air bags, padded steering wheel, shoulder strap in the seat belt, etc,

I was grateful for an engine, 3 speed automatic, 4 tires (whitewalls!!), an AM radio with 1 speaker and they were all connected together and working.

Most drivers are not prepared for a sudden component failure or multiple failures. Not for their cars or the cars next to them. They really need to teach that in driver education classes with specially rigged cars on a closed course.

 

[Rachey]

Im having the same issue stuck in park and flashing P cannot reverse or drive and can hear a humming noise. JAGUAR assistance here now saying the car needs a new small battery to the front but cannot fix it until four days later! we;ll see what the outcome is. i mentioned to him about the wiring harness that ive read on here but he is adamant its only the battery that need replacing.

 

[Ayepace]

Im having the same issue stuck in park and flashing P cannot reverse or drive and can hear a humming noise. JAGUAR assistance here now saying the car needs a new small battery to the front but cannot fix it until four days later! we;ll see what the outcome is. i mentioned to him about the wiring harness that ive read on here but he is adamant its only the battery that need replacing.

Yes it could be only the small battery. That small battery powers the parking lock, the front EPIC (electronics for the front motor) and power brake booster. This shouldn't work if the wiring harness is broken.

If you have the means to apply a 12V battery charger to the small battery, you could test the ability to get it out of park, although I don't recommend driving somewhere and getting stuck there.

 

[rcomeau]

Im having the same issue stuck in park and flashing P cannot reverse or drive and can hear a humming noise. JAGUAR assistance here now saying the car needs a new small battery to the front but cannot fix it until four days later! we;ll see what the outcome is. i mentioned to him about the wiring harness that ive read on here but he is adamant its only the battery that need replacing.

4 days! Consider yourself lucky. It took weeks to get the aux battery a couple of months ago. How old is the car? Make sure they they do the appropriate tests to know why the battery failed (the tow guy is not able to decide that on the spot). I had the battery go dead (either the starter and/or aux battery) multiple times. The issue may not be the battery but the sofware and/or electronics that manage the batteries and that failing allows the battery to go dead. My first tow last summer was "solved" with a software reload. The second time they replaced the module (sorry, I'd have to look back to see which one, but BCM?) and the third time they replaced the batteries (finally) and the BCM again as it seemed to throw errors. Total time in the shop for the 3 issues was 2-3 months over a 9 month period. Sorry to sound alarming, but this seems to be the Achilles heel of the car (and other EVs apparently).

 

[Trielectric]

Was refreshing my knowledge of the wiring harness problem and decided to figure out where the problem actually is. It appears that all the problems listed have to do with the parking pall connection. ? So I combined some pictures to envision where the problem with the pawl is. It appears that all we need is a big hole saw for the floorboard cut and a piece of wire with two crimp connectors to fix it! Please feel free to correct me if you think I am mislabeling something.

 

[dcdrive]

a piece of wire with two crimp connectors to fix it!

From the picture it looks like the issue is exclusive to the black wire. Why's that you think ?
And (hard to tell what the moving parts are), does lowering the suspension relieve some strain ?

 

[lobster]

I recall reading that there was a problem with the parking pall conector having two possible failure modes. One fault required inspecting the connector pins for water ingress and corrosion, and the second fault was suspected excessive tension on the wires causing separation from the connector pins.

Corroded connections to the parking pall required replacement of the whole parking pall module, requiring extensive disassembly.

If the parking pall connector wiring had fractured from movement of the motor assembly or faulty workmanship of the connector wiring this should be repairable onsite by competent automotive electrical worker. With the severe shortage of these wiring looms, I would expect that there should be enough of these for a batches to be reconditioned and tested offsite and promptly distributed to the dealers when required.

Cheers, Steve

 

[Trielectric]

From the picture it looks like the issue is exclusive to the black wire. Why's that you think ?
And (hard to tell what the moving parts are), does lowering the suspension relieve some strain ?

I agree that I think the main problem has been related to the parking pawl and the black wire is the wire that is pulled the tightest. I am sure the motor/inverter/transmission are soft mounted to the chassis. I believe you can see one of the mounts in the picture, behind my highest red arrow. It has a taper angle to it. That means the wiring harness does get some flex to it.

 

[Ayepace]

It is probably impossible to repair the connector until the whole thing has been removed from the car due to lack of working room. They might as well replace the harness at that point for a permanent fix.

The picture below from the service bulletin shows a case of the red wire broken as well as others. It isn't just the black wire that can break.

The black wire goes to ground, red (battery + ), white with violet stripe (wake up line), white with blue stripe (park lock position feedback), and brown with white stripe (actuator command line). You can't be colour blind to work on wiring harnesses.

 

[Trielectric]

From appearances in the photos above:
Two of wires (black wire & white with brown wire) appear to have been cut, not pulled from the plug. I do not see a red wire separated.? Everything we have heard is that the failures are due to a wiring harness that is too short. I would have thought the wires would have some end coloration if they had pulled loose while powered (they only vibrate when powered). Could be a Putin saboteur.

 

[Ayepace]

The wires won't pull loose from the connector. The metal contacts at the ends of wires lock into the plastic connector piece and there is a seal around the wires too to keep out moisture.

Breaking where a wire meets the seal would be a reasonable thing to find since this would be the stress point of a short harness.

These are not high voltage wires and unlikely to cause a spark or anything else that would discolor the severed ends. The small gauge wire breaks and then the insulation breaks.

 

[Amphungry]

My cat is stranded since mid-December at Décarie Motors for exactly same problem...
Intermittent power train failures upon acceleration. Had experienced the same grinding sound only once though....

The park lock activator is broken and we are still waiting for the part to come in....
They are talking about a 25-30 hours job to replace the part....

Yes experienced this also.. gerrrrr

Replacing the " park lock activator" work out for you ?

thanks

 

[DocHudson]

Got "gearbox Fault Detected" message while driving home from work last Friday. Didn't notice grinding sounds, but thinking after the incident I did notice some brief unusual sounds while driving intermittently over the last few weeks. No grinding sounds were noticed during the drive when fault message appeared. Drove home without incident and parked in garage. After parking, the "P" light was flashing. Turning off the car and then restarting reinitiated the gearbox fault warning. Selecting drive or reverse also resulted in the indicator flashing and there was no movement forward or reverse if "go" peddle was pressed.

Finally setup a tow to the local dealership today, JLR Willow Grove. After receiving the car, the dealership reported it was a "front wire harness came loose". They said they ordered the parts and were hoping to receive them late this week. Dealer stated they had qualified tech on site and would update me early next week. No loaner available until early next week.

Hoping for a quick resolution and somewhat relieved that the issue will be fixed and won't be something to be concerned about down the road, especially after the warranty expires! I'll update this thread as I find out more details.

A couple of picks attached including tow hook used to pull onto flatbed.

 

[Qtown charger]

Sorry to hear. But agreed, it is reassuring to have the issue now rather than in 2yrs time.
Interested to hear how Willow Grove works out compared to my experiences at Allentown.

 

[DocHudson]

Sorry to hear. But agreed, it is reassuring to have the issue now rather than in 2yrs time.
Interested to hear how Willow Grove works out compared to my experiences at Allentown.

They seem confident in a relatively quick fix. We'll see. I added picture of fault on instrument cluster in my post above.

I also asked for a TCU upgrade from 14.2 to 20.2 based on "intermittent connectivity issues". This is the third request. Maybe it will be the charm.

Should I be asking for software upgrades to other modules?